Evaluation of effects of limited irrigation on regional-scale water movement and salt accumulation in arid agricultural areas

2022 ◽  
Vol 262 ◽  
pp. 107398
Author(s):  
Wei Mao ◽  
Yan Zhu ◽  
Jingwei Wu ◽  
Ming Ye ◽  
Jinzhong Yang
Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 692
Author(s):  
Boyu Mi ◽  
Haorui Chen ◽  
Shaoli Wang ◽  
Yinlong Jin ◽  
Jiangdong Jia ◽  
...  

The water movement research in irrigation districts is important for food production. Many hydrological models have been proposed to simulate the water movement on the regional scale, yet few of them have comprehensively considered processes in the irrigation districts. A novel physically based distributed model, the Irrigation Districts Model (IDM), was constructed in this study to address this problem. The model combined the 1D canal and ditch flow, the 1D soil water movement, the 2D groundwater movement, and the water interactions among these processes. It was calibrated and verified with two-year experimental data from Shahaoqu Sub-Irrigation Area in Hetao Irrigation District. The overall water balance error is 2.9% and 1.6% for the two years, respectively. The Nash–Sutcliffe efficiency coefficient (NSE) of water table depth and soil water content is 0.72 and 0.64 in the calibration year and 0.68 and 0.64 in the verification year. The results show good correspondence between the simulation and observation. It is practicable to apply the model in water movement research of irrigation districts.


2019 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Ana Paula Dias Turetta ◽  
Bruno Pedrosa ◽  
Luca Eufemia ◽  
Michelle Bonatti ◽  
Stefan Sieber

Open data are important for adding legitimacy and transparency to public sciences. These data have also a potential to be used as a first approach for scientific investigation, such as spatial evaluation of ecosystem services. This paper presents a methodological approach to evaluate the trade-offs between agriculture and supporting ecosystem services based on spatial analysis and open data. The study area is an important agricultural production region in Bahia State, Brazil. The framework was able to establish the spatial interactions between agriculture and ecosystem service provision, while the regional scale was useful in supporting guidelines regarding sustainable land use for agricultural areas.


2019 ◽  
Vol 88 (2) ◽  
pp. 23-32
Author(s):  
Franco Carpegna ◽  
Giovanni Soldato ◽  
Roberto Toffoli

During the Spring of 2011, we studied the bird community in an area of Val Borbera, in the province of Alessandria (NW Italy). In the study area, situated at an altitude between 655 and 1700 m a.s.l., we conducted 110 points count ten minutes each in four microhabitats (agricultural areas, shrubs, forests, and prairies). In total, we surveyed 72 species, of which 51 were passerine and 21 non passerine. The most abundant species were Sylvia atricapilla, Phylloscopus collybita, Apus apus, and Turdus merula. In the agricultural areas, we detected a total of 50 species (Sylvia atricapilla, Parus major, Turdus merula were the most abundant). In the shrubs, we detected 30 species (Sylvia atricapilla, Parus major, Fringilla coelebs, Phylloscopus collybita, Turdus merula, Erithacus rubecula were the most abundant). In the forest areas, we found 45 species (Sylvia atricapilla, Parus major, Fringilla coelebs, Phylloscopus collybita, Turdus merula, Erithacus rubecula were the most abundant), and in the prairies, we detected 48 species (Alauda arvensis, Anthus campestris, Sylvia atricapilla, Turdus merula, Anthus trivialis, Sylvia communis were the most abundant). Compared to the other macro habitats, the agricultural areas have a significantly high abundance and richness in species, which highlights the importance of the agricultural mosaics in the Piedmont and mountain areas. The data which has been collected so far confirms the important role of this area, given the presence of some species which are rare at a regional scale.


Author(s):  
B. Tavus ◽  
S. Kocaman ◽  
C. Gokceoglu

Abstract. Although dams are very useful engineering structures, they can have extremely harmful consequences if they fail. One example of these failures occurred in Sardoba Reservoir (Uzbekistan). On May 1, 2020, a part of an earthfill dam failed along the Sardoba Reservoir, and a large region with settlements and agricultural areas in Uzbekistan and Kazakhstan was flooded. Accurate mapping and monitoring of the flooded areas are crucial for the damage assessment and the mitigation efforts. Satellite Earth Observation datasets can serve for these purposes due to their greater availability with high spatial and temporal resolutions. However, the optical sensors have limitations for data acquisition due to the atmospheric conditions, particularly the cloud cover, which often severely affects the image usability when floods occur. The synthetic aperture radar sensors provide valuable information under all weather conditions, but their interpretation is relatively difficult. Therefore, a data fusion methodology is proposed here for the integrated use of Sentinel-1 and Sentinel-2 datasets using a set of features obtained from both. Four different feature combinations were evaluated using the random forest classifier. The pre-processing steps for the feature extraction are explained in detail and the results are discussed here. The proposed algorithm exhibits very high classification accuracy for the flooded areas and flooded vegetation classes. The method can be employed for the flash flood mapping at regional scale. In addition, the damage assessment especially for agricultural areas in the region is very important for accounting the economic losses and the resilience purposes.


2018 ◽  
Vol 9 (4) ◽  
pp. 691-702 ◽  
Author(s):  
G. G. Morianou ◽  
N. N. Kourgialas ◽  
G. Psarras ◽  
G. C. Koubouris

Abstract The objective of this work was to classify and map the areas environmentally sensitive to desertification in the Mediterranean island of Crete. Sensitivity to desertification was estimated with a modification of the MEDALUS Environmentally Sensitive Area Index (ESAI) approach, using 15 quantitative parameters divided into four main quality indices: climate, vegetation, soils and management quality. The ESAI methodology was modified to include two additional parameters related to soil quality (water erosion and soil organic matter). According to the results, 37% of the island's area is characterized as critically sensitive to desertification. This percentage varies significantly across the island, with the western part having the least critically sensitive areas, and the eastern part the most critically sensitive. The results of this study also indicate that critically sensitive areas are found in the eastern side of the island mainly due to human-related factors and climatic conditions. It was concluded that the proposed methodology is a valuable tool for regional-scale assessment of areas environmentally sensitive to desertification in Mediterranean environments.


Author(s):  
Ning Zhang ◽  
Weihao Wang

In Southwest Louisiana, the Calcasieu Lake and surrounding water systems are the major fresh water sources to the nearby coastal wetlands and agricultural areas. There are two national wide life refuges located in both east and west sides of Calcasieu Lake. Both refuges are covered by coastal wetlands. The health of the wetland vegetation is essential to the wetland losses in the area. One of the major problems related to the health of marshes is the nutrient deficiency. In addition, the surface water system is a possible source for agriculture use that requires sufficient nutrient components in water. Understanding the transport and distribution of various nutrients in the coastal water system is very important to the above-mentioned issues. In this study, a regional scale hydrodynamic model was utilized to simulate the hydrodynamics, salinity transport and sediment transport in this major water system in Southwest Louisiana. The pH distribution in water is a good indication of many nutrient components, such as phosphorous, and is essential to understand the nutrient distributions in the target area. A pH calculation procedure was implemented in the model to determine pH values based on the salinity and other water properties. The model results can be used to indicate the dynamic change of nutrient distributions and the areas of nutrient deficiency.


2020 ◽  
Vol 66 (5) ◽  
pp. 568-577 ◽  
Author(s):  
Ofir Katz ◽  
Ilan Stavi

Abstract One method of controlling dune encroachment is afforestation, which may result in biodiversity loss because of habitat change and adverse effects of trees on ecosystem functioning. We carried out a study on the effects of planting discrete areas with Tamarix aphylla (L.) Karsten trees, over 50 years ago, in a semiarid dunefield in the northern Negev, Israel. We surveyed the vegetation and sampled litter and soil in five microhabitats formed by this afforestation scheme. Afforestation had spatially and functionally hierarchical effects on vegetation and plant diversity. The strongest effect was associated with land-use change, showing reduced species richness (by 30–50 percent) and litter production following afforestation. The second strongest effect was associated with salt accumulation in T. aphylla leaves and litter, which increases soil salinity under T. aphylla canopies by 4–5, forming “salinity islands,” and leading to over 30 percent decrease in plant cover and aboveground biomass. The assumed effect of trees in blocking solar irradiance and wind was observed only outside canopies and had a weak impact on plant cover. Therefore, afforestation can increase plant diversity at the regional scale, but at the local (microhabitat) scale it has an overall adverse effect on measured ecosystem functions.


2006 ◽  
Vol 21 (1) ◽  
pp. 103-109 ◽  
Author(s):  
C. M. Larry Lopez ◽  
A. Brouchkov ◽  
H. Nakayama ◽  
F. Takakai ◽  
A. N. Fedorov ◽  
...  

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